It's a bit on the techy side but if you absolutely positively have to know how much sun you are getting this is a decent option not to mention, quite the conversation starter. The UV Smart Bikini features a handy-dandy UV meter with an LED display on the bikini bottom. The meter is waterproof, washable and pool-safe. The $190 bikini
is flattering enough (if a bit Star Trek meets Beach Blanket Bingo) on the model shown but I don't think this would work on many body types.
[via Core 77